The present invention is directed to a new and useful film. Films, and especially heat shrinkable films are well known for many packaging applications. An example is D-955 film supplied commercially by W. R. Grace. This film has proven to be very useful in packaging applications where high shrink, good optics, and other desirable features of the packaging film are needed. These additional features include impact resistance, tear initiation and tear propagation resistance. Films of this type are disclosed in U.S. Pat. Nos. 4,551,380 and 4,643,943, both to Schoenberg, incorporated herein by reference in their entirety.
It would be desirable to use heat shrinkable materials like D-955 in end use applications requiring relatively high stiffness, i.e. high tensile modulus. One example of such an end use is on certain high speed packaging machines. Unfortunately, these films do not have sufficient stiffness to provide an optimal packaging material for such uses.
It would also be desirable to provide a material that has a reduced thickness compared to many commercial films. This would offer reduced costs in manufacture, because of the reduction in the amount of raw material used to make the film. It would also offer an environmentally attractive film because of source reduction. However, in attempting to achieve this by simply downgauging currently available films, degradation of film properties can occur. These properties include tensile modulus (stiffness), which as already pointed out is already marginal or unacceptably low for some packaging applications; heat seal strength, and impact resistance.
It would in addition be desirable to provide a material that has a reduced shrink force compared to many commercial films. This would offer utility in packaging applications where the product to be packaged is sensitive to high shrink forces, and can be distorted by such films when heat shrunk around the product.